Steam keeps asking for accessibility features even though is has access?
Solution 1:
A temporary fix (requires terminal):
sudo sqlite3 /Library/Application\ Support/com.apple.TCC/Tcc.db 'delete from access where client like "%Steam%"'Restart Steam
Allow steam access in accessibility via UI or something like:
sudo sqlite3 /Library/Application\ Support/com.apple.TCC/TCC.db "INSERT OR REPLACE INTO access values ('kTCCServiceAccessibility','com.valvesoftware.steam',0,1,0,NULL);"
Solution 2:
This seems to be a known bug for Yosemite.
Steam has to be updated to work 100% with compatibility for Yosemite. Just wait for them to fix it.